chapter 10: biological rhythms and sleep

Question 1

biological rhythms

Answer 1

a regular fluctuation in any living processes

Question 2

circadian rhythm

Answer 2

a pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period

Question 3

ultradian

Answer 3

referring to a rhythmic biological event whose period is shorter than that of a circadian rhythm, usually from several minutes to several hours long

Question 4

infradian

Answer 4

referring to a rhythmic biological even those period is longer than that of a circadian rhythm (longer than a day)

Question 5

diurnal

Answer 5

active during the light periods of the daily cycle

Question 6

nocturnal

Answer 6

active during the dark periods of the daily cycle

Question 7

free-running

Answer 7

referring to a rhythm of behavior shown by an animal deprived of external cues about time of day

Question 8

period

Answer 8

the interval of time between two similar points of successive cycles, such as sunset to sunset

Question 9

phase shift

Answer 9

a shift in the activity of a biological rhythm, typically provided by a synchronizing environmental stimulus

Question 10

entrainment

Answer 10

the process of synchronizing a biological rhythm to an environmental stimulus

Question 11

zeitgeber

Answer 11

the stimulus (usually the light-dark cycle) that entrains circadian rhythms

Question 12

suprachiasmatic nucleus (SCN)

Answer 12

a small region of the hypothalamus above the optic chasm that is the location of the circadian clock

Question 13

melatonin

Answer 13

an amine hormone that is secreted by the pineal gland at night, thereby signaling day length to the brain

Question 14

retinohypothalamic pathway

Answer 14

the route by which retinal ganglion cells send their axons to the suprachiasmatic nucleus

Question 15

melanopsin

Answer 15

a photopigment found within particular retinal ganglion cells that projects to the suprachiasmatic nucelus

Question 16

electroencephalography (EEG)

Answer 16

the recording and study of gross electrical activity of the brain via large electrodes placed on the scalp

Question 17

slow-wave sleep (SWS)

Answer 17

sleep, divided into stages 1-3, that is defined by the presence of slow-wave EEG activity; also called non-REM sleep

Question 18

rapid-eye-movement (REM) sleep

Answer 18

a stage of sleep characterized by small-amplitude, fast-EEG waves, no postural tension, and rapid eye movements; also called paradoxical sleep

Question 19

desynchronized EEG

Answer 19

a pattern of EEG activity comprising a mix of many different high frequencies with low amplitude

Question 20

alpha rhythm

Answer 20

a brain potential of 8-12 hertz that occurs during relaxed wakefulness

Question 21

vertex spike

Answer 21

a sharp-wave EEG pattern that is seen during stage 1 sleep

Question 22

stage 1 sleep

Answer 22

the initial stage of slow-wave sleep, which is characterized by small-amplitude EEG waves of irregular frequency, slow heart rate, and reduced muscle tension

Question 23

stage 2 sleep

Answer 23

a stage of slow-wave sleep that is defined by bursts of regular 14- to 18-hertz EEG waves called sleep spindles

Question 24

sleep spindle

Answer 24

a characteristic 14- to 18- hertz wave in the EEG of a person said to be in stage 2 sleep

Question 25

K complex

Answer 25

a sharp, negative EEG potential that is seen in stage 2 sleep

Question 26

stage 3 sleep

Answer 26

a stage of slow-wave sleep that is defined by the presence of large amplitude, slow delta waves

Question 27

delta wave

Answer 27

the slowest type of EEG wave, characteristic of stage 3 sleep

Question 28

nightmare

Answer 28

a long, frightening dream that awakens the sleeper from REM sleep

Question 29

night terror

Answer 29

a sudden arousal from stage 3 sleep that is marked by intense fear and autonomic activation

Question 30

sleep deprivation

Answer 30

the partial or total prevention of sleep

Question 31

sleep recovery

Answer 31

the process of sleeping more than normally after a period of sleep deprivation, as though in compensation

Question 32

ecological niche

Answer 32

the unique assortment of environmental opportunities and challenges to which each organism is adapted

Question 33

isolated brain

Answer 33

an experimental preparation in which an animal's brainstem has been separated from the spinal cord by a cut below the medulla

Question 34

isolated forebrain

Answer 34

an experimental preparation in which an animal's nervous system has been cut in the upper midbrain, dividing the forebrain from the brainstem

Question 35

basal forebrain

Answer 35

a ventral region in the forebrain that has been implicated in sleep

Question 36

tuberomamillary nucleus

Answer 36

a region of the basal hypothalamus, near the pituitary stalk, that plays a role in generating slow-wave sleep

Question 37

general anesthetic

Answer 37

a drug that renders an individual unconscious

Question 38

reticular formation

Answer 38

an extensive region of the brainstem (extending from the medulla through the thalamus) that is involved in arousal (awaking); also called reticular activating system

Question 39

locus coeruleus

Answer 39

a small nucleus in the brainstem whose neurons produce norepinephrine and modular large areas of the forebrain

Question 40

narcolepsy

Answer 40

a disorder that involves frequent, intense episodes of sleep, which last from 5 to 30 minutes and can occur anytime during the usual waking hours

Question 41

cataplexy

Answer 41

sudden loss of muscle tone, leading to collapse of the body without loss of consciousness; sometimes a common component of narcoleptic attacks

Question 42

hypocretin

Answer 42

a neuropeptide produced in the hypothalamus that is involved in switching between sleep states, in narcolepsy, and in the control of appetite; also called orexin

Question 43

sleep paralysis

Answer 43

a state, during the transition to or from sleep, in which the ability to move or talk is temporarily lost

Question 44

sleep enuresis

Answer 44

bed-wetting

Question 45

somnambulism

Answer 45

sleepwalking

Question 46

REM behavior disorder (RBD)

Answer 46

a sleep disorder in which a person physically acts out a dream

Question 47

sleep-onset insomnia

Answer 47

difficulty in falling asleep

Question 48

sleep-maintenance insomnia

Answer 48

difficulty in staying asleep

Question 49

sleep apnea

Answer 49

a sleep disorder in which respiration slows or stops periodically, waking the patient; excessive daytime sleepiness results from the frequent nocturnal awakening

Question 50

sudden infant death syndrome (SIDS)

Answer 50

the sudden, unexpected death of an apparently healthy human infant who simply stops breathing, usually during sleep; also called crib death

Question 51

sleep state misperception

Answer 51

commonly, a person's perception that he has not been sleeping which in fact he has; typically occurs at the start of a sleep episode